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A quick post on how to get the most out of our Patchblocks for Eurorack module and get it communicating with other Eurorack modules, by looking at how the module hardware interacts with the Patchblocks software environment.

We're going to look at how to send inputsignals into the DSP environment and change the DC offset of the signal, how to send triggers and gates signals to and from the module, syncing Patchblocks oscillators with other oscillators in a modular system, and how to use control voltages to change parameters in a patch or to use the CV inputs as additional audio inputs. ​

INPUT SIGNALS

The module hardware scales incoming bi-polar voltages of +10v/-10v to a range that is read by the Audio Input block (see pic above), the signals are then mapped to the range of 0.5 to -0.5 in the Patchblocks editor.

So, a bi-polar input voltage of 20 volts peak to peak will be in the range -0.5 to 0.5 in the Patchblocks editor, a unipolar voltage of 0 to +10v peak to peak will be in the range 0 to 0.5 in the Patchblocks editor.

There is a slight DC Offset on the hardware, to compensate for this we can use the Add block in the software to subtract a value of -0.05. This will set the zero crossing point of the incoming bi-polar signal to 0 in the Patchblocks editor.

The left input on the module (IN) corresponds to the Left analogue channel in the Audio Input block, the right input the Right analogue channel. As of software update 0.5.3 the Audio Input block adds code to invert the incoming signal. This corrects the inversion on the module hardware, so incoming signals will be in phase with signals generated in the editor. ​

GATE/TRIGGER INPUTS

The GATE inputs on the module are inputs for the 2 buttons in the Patchblocks editor, which are accessible using the Controls block. Pressing the button will activate the function the control is assigned to in the patch. Instead of pressing the button, an incoming voltage of amplitude +5v will also activate a button press.

In this patch above, the two buttons are assigned to trigger two small samples, deux and un. The samples can also be triggered by a short pulse of +5v sent to the GATE input.

We've tested the speed/response of the GATE inputs with incoming triggers of speeds down to 50 micro seconds. If you're having trouble with triggering samples or drums, make sure the Amplitude of the Input signal is high enough - it's expecting a +5v signal.

The GATE inputs are not velocity sensitive; the input is read as a value of either 0 or 1 in the Patchblocks editor. However they are time sensitive, so a +5v pulse of a longer duration can be used to trigger the length of an envelope in the editor. ​

Sending trigger or gate signals from the module

The triggers in the Patchblocks editor are normally short negative polarity pulses. To convert these to positive polarity triggers of +5v, we need to perform a couple of functions in the editor.

This patch above takes triggers from the GATE inputs (which could also be triggers generated anywhere in the Patchblocks Editor for example from the Impulse block), converts them to random triggers and division of 3 triggers, and routes them to the two Audio Outputs. If we look at the two blocks before the Audio Output, the Gate block in the editor can be used to set the length or duration of the output trigger, and the Multiply block contains a value of -1, which inverts the trigger signal from a negative polarity pulse to a positive polarity pulse. ​

SYNCING Patchblocks oscillators with other oscillator modules

The GATE inputs can also be used to sync Patchblocks oscillators with other oscillators in a Eurorack system.

Patchblocks oscillators have a Reset input, which if a non-zero value is received (say a value of 1), will hold it's output at the peak of the wave until the duration of the reset signal is complete (back to 0). A trigger signal of +5v amplitude at the GATE inputs can be used as a reset signal for the oscillators in the Patchblocks Editor.

The control voltage inputs

Similar to the GATE inputs, the CV inputs are control voltage inputs for the 2 assignable knobs in the Patchblocks editor, accessed using the Controls block.

On the hardware these inputs are expecting a bi-polar input signal of -5v to +5v, although signals of higher amplitudes can also be sent. This signal is then mapped to a range of 0 to 1 in the Patchblocks editor.

The CV inputs can also be used as audio inputs by using the Add block in the editor and adding a value of -0.5 - this will bring the range of the input signal into the same range in the editor as the Audio Input block (-0.5 to 0.5).

When an input signal is present, the control knob acts as an attenuator - roll it all the way to the left to allow the full CV signal through or increase clockwise to attenuate the amount of the CV signal affecting the patch parameter. If you have a version 0.9 PCB (check the silkscreen on the printed circuit board on the back of the module) then the CV inputs are inverted, if you have a version 1.0 PCB the CV inputs are not inverted.

That's it for now! Hopefully the above tips will help to get the most out of using the Patchblocks module with other modular and non-modular gear, if you have any comments or questions please let us know in the comments or shout us email at info (at) maker.ie. Happy patching!

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